From: Markos Chandras <markos.chandras@imgtec.com>
Date: Mon, 23 Jun 2014 09:38:51 +0000 (+0100)
Subject: MIPS: bpf: Fix branch conditional for BPF_J{GT/GE} cases
X-Git-Tag: firefly_0821_release~176^2~3687^2~12
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1ab24a4e3de1ec37d8ed255841d2d94d77e8a4f4;p=firefly-linux-kernel-4.4.55.git

MIPS: bpf: Fix branch conditional for BPF_J{GT/GE} cases

The sltiu and sltu instructions will set the scratch register
to 1 if A <= X|K so fix the emitted branch conditional to check
for scratch != zero rather than scratch >= zero which would complicate
the resuling branch logic given that MIPS does not have a BGT or BGET
instructions to compare general purpose registers directly.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: netdev@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7126/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---

diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 8cae27af03da..500f97fdc0e1 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -1127,7 +1127,7 @@ jmp_cmp:
 				}
 				/* A < (K|X) ? r_scrach = 1 */
 				b_off = b_imm(i + inst->jf + 1, ctx);
-				emit_bcond(MIPS_COND_GT, r_s0, r_zero, b_off,
+				emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off,
 					   ctx);
 				emit_nop(ctx);
 				/* A > (K|X) ? scratch = 0 */